1. Field of the Invention
The present invention relates to an active suspension apparatus for a vehicle and a pump thereof, and more particularly, to an active suspension apparatus for a vehicle that supplies a fluid to an actuator disposed at a wheel of the vehicle using a pump that is driven by a motor and a pump of the active suspension apparatus for the vehicle.
2. Discussion of Related Art
Active suspension systems for vehicles are systems that sense various inputs received from a road using a sensor and effectively control a rolling action of a vehicle, using an electric control unit (ECU) based on the sensed inputs.
In detail, an active suspension system for a vehicle includes an actuator that compensates for a displacement of a coil spring connected to a wheel of the vehicle and performs a function of properly controlling the volume of a fluid supplied to the actuator, by sensing rolling and pitching actions of the vehicle so as to maintain a body of the vehicle garage at a constant level so that riding quality and road traction force of the vehicle can be improved.
Furthermore, the active suspension system for the vehicle may enable a driver to set a height of the body of the vehicle according to the state of the road through level control of the body of the vehicle or may reduce an air resistance by lowering the body of the vehicle at a high speed, thereby performing a function of improving stability in driving and a fuel consumption ratio.
In connection with the active suspension system, U.S. Pat. No. 6,000,702 discloses technical content which includes a spring and a lift-adjustable regulating unit that is connected to the spring in series and in which a flow rate of a fluid supplied to the lift-adjustable regulating unit is controlled using a proportional control valve.
However, in the technical content, there is a problem that a high-priced proportional control valve and hydraulic pump need to be used. Furthermore, since the hydraulic pump is connected to an engine and is always driven, when the engine is in an operating state, the hydraulic pump needs to be always driven so as to generate a high-pressure source. Thus, an excessive capacity that is not required by a system is unnecessary, and an output of the engine is lowered, which results in a negative influence on a fuel consumption ratio.